﻿// Copyright (c) 2014 AlphaSierraPapa for the SharpDevelop Team
// 
// Permission is hereby granted, free of charge, to any person obtaining a copy of this
// software and associated documentation files (the "Software"), to deal in the Software
// without restriction, including without limitation the rights to use, copy, modify, merge,
// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
// to whom the Software is furnished to do so, subject to the following conditions:
// 
// The above copyright notice and this permission notice shall be included in all copies or
// substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.

using System;
using Microsoft.Win32;

namespace ICSharpCode.PackageManagement.Scripting
{
	public class PowerShellDetection : IPowerShellDetection
	{
		public static readonly string PowerShellRegistryKeyName = 
			@"SOFTWARE\Microsoft\PowerShell\1\PowerShellEngine";
		
		public static readonly string PowerShellVersionRegistryValueName =
			"PowerShellVersion";
		
		public bool? installed;
		
		public bool IsPowerShell2Installed()
		{
			if (!installed.HasValue) {
				installed = CheckIfPowerShell2IsInstalled();
			}
			return installed.Value;
		}
		
		bool CheckIfPowerShell2IsInstalled()
		{
			RegistryKey key = OpenPowerShellRegistryKey();
			if (key != null) {
				using (key) {
					return IsPowerShell2Installed(key);
				}
			}
			return false;
		}
		
		RegistryKey OpenPowerShellRegistryKey()
		{
			return Registry.LocalMachine.OpenSubKey(PowerShellRegistryKeyName);
		}
		
		bool IsPowerShell2Installed(RegistryKey key)
		{
			string readValue = GetPowerShellVersion(key);
			return readValue == "2.0";
		}		
		
		string GetPowerShellVersion(RegistryKey key)
		{
			return (string)key.GetValue(PowerShellVersionRegistryValueName);
		}
	}
}
